1. Field of the Invention
The present invention relates to a disc identifying device, applied to a disc drive apparatus for reproducing information recorded on a disc and/or recording desired information on the disc, for identifying the type (size) of the disc when the disc is inserted into the apparatus.
2. Description of the Related Art
Conventionally, an 8 cm diameter optical disc (a small diameter disc), as well as a 12 cm diameter optical disc (a large diameter disc) has been known as a recording medium for recording information, for example music information. A disc drive apparatus for recording desired information on that type of disc or reproducing the recorded information therefrom has also been known. One type of the known disc drive apparatus is what is called a slot-in type disc drive apparatus, in which a disc inserted into an insert slot is transferred directly without using a tray for loading the disc to a drive position inside the apparatus by a transfer mechanism.
The time that takes for a disc to reach the drive position is different between the large diameter disc and the small diameter disc because of their difference in diameter. Therefore, the way in which the disc is transferred should change depending on the disc size because disc sizes cannot be positioned appropriately at the drive position. In addition, with models that do not support the small diameter disc, a problem arises that, for example, the small diameter disc is not guided to the drive position so that the disc cannot be removed from the inside of the apparatus.
For that reason, the slot-in type disc drive apparatus is usually provided with a disc identifying device for identifying whether the disc inserted into the insert slot of the apparatus is a large diameter disc or a small diameter disc.
A known example of such a disc identifying device is as follows (See, for example, Patent Document 1: JP-A-2002-042399 Paragraphs [0018] through [0021], FIGS. 1 through 3). The device has a pair of left and right pins slidable along a longitudinal direction of the insert slot and three switches disposed along the movement paths of the two pins. When a small diameter disc is inserted, one or two of the three switches is/are switching-operated by the pins and is/are turned on while a large diameter disc is inserted, all the three switches are switching-operated by the pins and are turned on.
According to Patent Document 1, three switches make it possible to identify whether the disc inserted in the insert slot is a large diameter disc or a small diameter disc, and allow the movable parts in the apparatus to operate appropriately.
However, the disc identifying device using the three switches for identifying two sizes of discs as disclosed in Patent Document 1 has a high cost in relation to the parts count and requires a complicated electric circuit for processing the output signals from those switches. In addition, the just-described disc drive device may occur a poor productivity in relation to fitting of the three switches. Moreover, it is necessary to ensure the space for accommodating the three switches which hinders size reduction of the apparatus.